How to use API to get an object's constrained position?
After much digging around I believe for this simple case I can get what I need in D.objects['Empty'].matrix_local. E.g.

&gt;&gt;&gt; D.objects['Empty'].matrix_local
Matrix(((1.0, 0.0, 0.0, -0.7031904458999634),
        (0.0, 1.0, 0.0, 0.0),
        (0.0, 0.0, 1.0, 0.29674994945526123),
        (0.0, 0.0, 0.0, 1.0)))
&gt;&gt;&gt; [D.objects['Empty'].matrix_local[i][3] for i in range(3)]
[-0.7031904458999634, 0.0, 0.29674994945526123]


There is also matrix_world (which is the same in this simple case). But if there is a better way to do this more generally, I hope someone will illuminate us.